1) I would make it a point to remind him every time you see him = This is what you get when you let someone do a job, that is NOT their job. And inevitably has no clue what they are doing.
And when they continue to do it, continue to raise your price higher & higher to fix what some random person should have never been messing with, to begin with. Eventually they will stop or not call you anymore, either way you will not have to deal with the stupid crap anymore.

2) Sennheiser has the RS-160. It use a small puck for a transmitter that will easily go behind the TV. Just get a 2nd power supply to run it, the 1st power supply chargers the headphones. Then you can set the headphones anywhere you want in the room.
One bad thing, you have to turn the transmitter on each time you use the RF headphones. So mount it where it is easy to reach - like on the edge of the TV back:
[Link: amazon.com]

As mentioned above by Eric, get an optical to analog adapter for the input. Here is a good one for cheap:
[Link: amazon.com]